Information devices have been developed to have higher performance and to have a higher pin count, leading to an increase in size of package substrates and semiconductor chips (semiconductor elements). A semiconductor package includes a package substrate and a semiconductor chip disposed on an upper surface of the package substrate. An example of a structure of a semiconductor package includes a ball grid array (BGA). In a BGA semiconductor package, the BGA balls (solder balls) are arranged in a grid array on a lower surface of the package substrate.
Japanese Laid-open Patent Publication No. 2000-286303 is an example of the related art.